Water is one of the most important resources for human and all known forms of lives on earth. Without water, most of the lives on earth, including human beings, are going to cease to exist. It seems that there are enough water resources on earth, as over 71% of the earth surface is covered by water. However, two factors make water become a scarce resource for most humans on earth.
First, not every types of water are similar. Human being and most other life forms as well, can only drink or use fresh water. However, on earth, 96.5% of the planet's water is found in seas and oceans. Only 2.5% of the earth's water is fresh water, and 98.8% of the fresh water is in ice and groundwater, which are not easily accessible. And less than 0.3% of the freshwater is in rivers, lakes and etc. Accordingly, only a very tiny portion of the total water on earth can be directly used by human.
Second, such small portion of fresh water is not evenly distributed among different regions. As for the regions with large fresh water body, such as river or lake, the fresh water supply may not be an issue. However, for many other regions where there is no river and lake nearby, and most of them being desert or other kind of arid areas, the availability of fresh water is a big concern, or even a health or life threatening issue. Moreover, even for the people to whom the availability of fresh water is not an issue, the quality of the fresh water may still be a big problem. Many of such rivers and lakes have already been polluted by industrial wastes, agricultural chemicals such as fertilizer and pesticides.
Water is the indispensable resource for human lives, as well as for most of the human activities, including drinking, washing, agriculture irrigation, industrial applications . . . etc. So, on one hand, human need more and more freshwater to support the life, activity and production. On the other hand, the availability and quality of fresh water is a serious issue.
In light of the foregoing, a wide variety of approaches have been developed to get more fresh water from other sources, such as brine in the ocean and the humidity in the atmosphere. Sea water desalination is a field with many well developed technologies, such as reverse osmosis, forward osmosis, molecular screening, electromagnetic deionization, vacuum distillation, multi-stage flash distillation, vapor compression desalination . . . etc. In many countries, sea water desalination is a vital source of fresh water supply. The world's largest desalination plant is the Jebel Ali Desalination Plant in the United Arab Emirates. However, all of the desalination processes are energy intensive and costly, hence these methods have major drawbacks. In addition, no matter how the desalination technology will be developed in the future, the fundamental physics law determines that a minimum energy consumption is a must, and it cannot be less than 1 kWh/m3.
Therefore, concerning the costs, the other approach that collects water from the atmosphere becomes more favorable; and this is especially true for the areas with the environmental and weather condition suitable for such an approach, such as many coastal arid areas and desert areas around the world.
In addition, due to the perpetual water cycle (hydrologic cycle) on earth, the water (moisture) in the atmosphere is inexhaustible and dynamic. The water is continuously exchanged between the atmosphere, soil water, surface water, groundwater, and plants. During this process, the water evaporates from oceans, rivers, lakes and other water bodies into the air. So the resource of moisture is always available for water collection.
Accordingly, one objective of the present invention is to design a new device for the water collection from the atmospheric moisture with the minimal energy input by humans and minimum human intervention and minimum maintenance, as well as utilizing the specific material with suitable properties as the water absorbing material in the device, so as to achieve the aforementioned objective.